/**
* Sets the various cache headers. Auto unsets 'Last-Modified'
* if $expires_offset is falsy.
*
* @param int|bool $expires_offset Time in seconds from now to cache.
* Pass 0 or false for no cache.
* @return $this
*/
public function setCacheHeaders($expires_offset = 86400)
{
$headers = Util::buildCacheHeaders($expires_offset);
// empty("0") is false negative
if (empty($expires_offset) || '0' === $expires_offset) {
unset($this->headers['Last-Modified']);
}
$this->setHeaders($headers);
return $this;
}
/**
* Returns an associative array of cache headers suitable for use in header().
*
* Returns the 'Cache-Control', 'Expires', and 'Pragma' headers given the
* expiration offset in seconds (from current time). If '0' or a value which
* evaluates to empty is given, returns "no-cache" headers, with Cache-Control
* set to 'no-cache, must-revalidate, max-age=0', 'Expires' set to a date in the
* past, and 'Pragma' set to 'no-cache'.
*
* @param int $expires_offset Expiration in seconds from now.
* @return array Associative array of cache headers.
*/
function http_build_cache_headers($expires_offset = 86400)
{
return Util::buildCacheHeaders($expires_offset);
}
